Researchers at the University of Michigan have made great progress in a unique technique that triggers laser light when blood is mixed with an FDA-approved fluorescent dye. The technique may expand the scope of cell structure visualization and early detection of tumors and cancerous cells.

Led by Biomedical Engineering professor Xudong (Sherman) Fan, the researchers claim in a published report to have made impressive strides. If the research succeeds in its goals, it will be a victory for enhanced clinical imaging and better monitoring of tumors.

The progress of the research was recently published in the Optical Society of America Technical Digest and acknowledged the rapid progress of blood-based lasers.

It may be recalled that, prior to the work on blood lasers, in 2011, a group of researchers successfully used a living kidney cell to amplify light.

In the first phase, the Michigan team successfully passed light into a small laser cavity filled with human blood mixed with Indocyanine green (ICG), a fluorescent dye approved by FDA.

Blood-based lasers are aiming to surpass the current limitations of conventional infrared, ultraviolet and visible light beams in visualizing tissues. They are faced with complaints of incoherence, low focus and opaque results.

In drug testing, too, blood lasers may become useful as they can foretell the changes in the cells when exposed to different drugs.

According to the researchers, ICG will not emit any laser by itself, but it can glow when mixed with blood. That follows a binding action with proteins and blood plasma that adds to the ability to amplify light.

"Without blood, just ICG, it doesn't work at all," Fan told New Scientist.

The process involves injecting the ICG into the bloodstream with a light beam tracked by an infrared camera. Although the blood laser research has proved successful only outside the human body, team leader Fan is confident of fluorescent infrared light working in the bloodstream as well. That may enable a surgeon to precisely pinpoint a tumor during a guided surgery.

His optimism hinges on the fact that ICG accumulates in blood vessels where large numbers of vessels are present. When more vessels are present, as in tumors, there will be significant glow, and it will serve as an indicator, asserted Fan.

The team is conducting more trials to zero in on the right reflective cavity before moving to the bloodstream. Professor Fan sees gold nanoparticles as ideal for that job.

"Eventually, we are trying to do it in the human body," Fan added.

Now, the challenge is to ensure the intensity of the light produced by the blood laser is not too strong and that no tissue is getting burnt.